亚适宜温光环境对黄瓜幼苗生长·光合特性和含氮量的影响

[目的]探讨亚适宜温光环境对黄瓜(Cucumis sativus L.)幼苗生长、光合特性和含氮量的影响,探讨亚适宜温光环境对黄瓜生长和光合机构的影响机理及植物对亚适宜温光逆境的适应机制。[方法]亚适宜温光处理5、10 d。亚适宜温度为18/12℃,亚适宜光照强度为(200±20)μmol/(m2.s)。[结果]亚适宜温光环境处理显著抑制了黄瓜幼苗的生长,降低了生物量的积累和叶片含氮量,但对黄瓜根系含氮量基本无影响;随处理时间的延长,叶绿素a和b含量先增加后降低,处理5 d时气孔限制为光合作用下降的主要限制因素,10 d时非气孔限制为光合作用降低的主要限制因素。[结论]该研究可为寻找调控亚适宜温光环境的有效措施,指导冬春季节设施黄瓜生产提供理论依据。

Effects of Suboptimal Temperature and Photo Flux Density Treatment on Growth,Photosynthetic Characteristics and Nitrogen Content of Cucumber(Cucumis sativus L.) Seedlings

[Objective] The purpose was to study the effects of suboptimal temperature and photo flux density treatment on growth,photosynthetic characteristics and nitrogen content of cucumber seedlings,and discuss its effects mechanism on growth and photosynthetic apparatus of cucumber and plants’ adaptive mechanism to adversity of suboptimal temperature and photo flux density.[Method] The suboptimal temperature and photo flux density was 18/12 ℃ and(200±20) μmol/(m2·s) respectively,and cucumber seedlings were treated in 5 and 10 days under this condition.[Result] The results showed that growth of cucumber seedlings were significantly inhibited,and the biomass accumulation and leaf nitrogen content were reduced by suboptimal temperature and photo flux density stress,but no influence on nitrogen content in cucumber roots;the content of chlorophyll a and b were increased after 5 d stress and then decreased for 10 d stress.The decline of net photosynthesis of cucumber seedlings under suboptimal temperature and PFD stress for 5 d were caused primarily by stomatal limitation,and the decline for 10 d were caused mainly by non-stomatal limitation.[Conclusion] The study provides a theoretical basis for finding out effective measures on controlling suboptimal temperature and photo flux density environment to guide greenhouse cucumber production in winter and spring.